Surging Idle and speedometer showing speed when stopped
Senior Member
Joined: Oct 2020
Posts: 586
From: Chicago, IL
I suggest you plan on replacing the alternator, it is beginning to fail. The speedo jumping is an indication the alternator diode pack is failing and allowing a significant ac (alternating current) ripple to pass through. The output speed sensor is particularly sensitive to ac ripple. The howling was also likely coming from your alternator.
How old is the battery and what condition is it in? Chryslers do not tolerate low voltage conditions and will throw all sorts of seemingly unrelated diagnostic codes (cat, evap, map, egr, etc). Suspecting you have a failing alternator, your battery is likely not fully charging and contributing to the myriad of diagnostic codes you are getting.
How old is the battery and what condition is it in? Chryslers do not tolerate low voltage conditions and will throw all sorts of seemingly unrelated diagnostic codes (cat, evap, map, egr, etc). Suspecting you have a failing alternator, your battery is likely not fully charging and contributing to the myriad of diagnostic codes you are getting.
Junior Member
Joined: Aug 2009
Posts: 6
My speedometer needle starts going up and down while stopped and in drive or reverse. There’s a consistent howling under the hood on passenger. I used Autozone code reader these are all the codes: P0455 = Evaporative emission system leak detected, P0457 = EESLD, P0456 = EESLD, P0420 = Catalyst statement efficiency below threshold, P0113 = Intake Air Temp., P0108 = Monifold Absolute Pressure, P0404 = Exhaust gas recirculation control circuit. I changed intake air temperature sensor and manifold absolute pressure sensors but SAME behavior.
Per this post, I suspected the alternator even though my codes were totally different. I disconnected the wires on the alternator (not the charging wire) and the problem disappeared. Could this mean the alternator is the cause?
Per this post, I suspected the alternator even though my codes were totally different. I disconnected the wires on the alternator (not the charging wire) and the problem disappeared. Could this mean the alternator is the cause?
- The speedo needle and array of sensor related codes def sounds like the alternator. Auto parts store should be able to test for free.
- I had P0455. Couldn't find it under the hood and had someone smoke test it. Turned out to be a cracked fitting that is built into the top of the gas tank. I think I lowered the tank, removed the hoses, and sealed crack with epoxy.
Good luck!
Junior Member
Joined: Jun 2021
Posts: 1
I have a 05 Pacifica 3.5L that was having surging idle, speedometer issues, jerking at light and just loud. It happened after I got gas at Sam's Club. I thought it was bad gas but it kept happening. No check engine light until they day before. Ran codes and it gave me P0700 and P0720. I was just going to replace the output speed sensor but after researching on here, I decided to check out my alternator. I turned my car on and turned on the AC until I hear the engine revving and the rpm creeping up. I removed the field connector off my alternator and the noise disappeared and it was no longer surging.
I needed the car fixed for work so I purchased a remanufactured alternator at Advance Auto Parts (use Rakuten for discount and cash back). Had it replaced and it doesn't seem to be exhibiting the same symptoms as before. I did take it back to the auto parts store and they said that it was still good and didn't fail any test but it was the original alternator. Money well spent. Drove it around for 30-45 mins and no engine codes, no jerking and no surging.
Money well spent!
I needed the car fixed for work so I purchased a remanufactured alternator at Advance Auto Parts (use Rakuten for discount and cash back). Had it replaced and it doesn't seem to be exhibiting the same symptoms as before. I did take it back to the auto parts store and they said that it was still good and didn't fail any test but it was the original alternator. Money well spent. Drove it around for 30-45 mins and no engine codes, no jerking and no surging.
Money well spent!
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Mauiguyy911
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Jan 21, 2020 02:20 PM
